June 2018 Update

Task/Identity-matrix/Go/identity-matrix-1.go

@@ -3,11 +3,11 @@ package main
 import (
     "fmt"
 
-    "github.com/gonum/matrix/mat64"
+    "gonum.org/v1/gonum/mat"
 )
 
-func eye(n int) *mat64.Dense {
-    m := mat64.NewDense(n, n, nil)
+func eye(n int) *mat.Dense {
+    m := mat.NewDense(n, n, nil)
     for i := 0; i < n; i++ {
         m.Set(i, i, 1)
     }
@@ -15,5 +15,5 @@ func eye(n int) *mat64.Dense {
 }
 
 func main() {
-    fmt.Println(mat64.Formatted(eye(3)))
+    fmt.Println(mat.Formatted(eye(3)))
 }

Task/Identity-matrix/Rust/identity-matrix.rust

@@ -0,0 +1,41 @@
+extern crate num;
+struct Matrix<T> {
+    data: Vec<T>,
+    size: usize,
+}
+
+impl<T> Matrix<T>
+where
+    T: num::Num + Clone + Copy,
+{
+    fn new(size: usize) -> Self {
+        Self {
+            data: vec![T::zero(); size * size],
+            size: size,
+        }
+    }
+    fn get(&mut self, x: usize, y: usize) -> T {
+        self.data[x + self.size * y]
+    }
+    fn identity(&mut self) {
+        for (i, item) in self.data.iter_mut().enumerate() {
+            *item = if i % (self.size + 1) == 0 {
+                T::one()
+            } else {
+                T::zero()
+            }
+        }
+    }
+}
+
+fn main() {
+    let size = std::env::args().nth(1).unwrap().parse().unwrap();
+    let mut matrix = Matrix::<i32>::new(size);
+    matrix.identity();
+    for y in 0..size {
+        for x in 0..size {
+            print!("{} ", matrix.get(x, y));
+        }
+        println!();
+    }
+}

Task/Identity-matrix/Stata/identity-matrix-1.stata

@@ -0,0 +1,8 @@
+. mat a = I(3)
+. mat list a
+
+symmetric a[3,3]
+    c1  c2  c3
+r1   1
+r2   0   1
+r3   0   0   1

Task/Identity-matrix/Stata/identity-matrix-2.stata

@@ -0,0 +1,8 @@
+: I(3)
+[symmetric]
+       1   2   3
+    +-------------+
+  1 |  1          |
+  2 |  0   1      |
+  3 |  0   0   1  |
+    +-------------+